1. Field of the Invention
The present invention relates to a liquid crystal display device and, more particularly, to an active matrix type of liquid crystal display device.
2. Description of the Related Art
An active matrix type of liquid crystal display device is characterized by a structure in which a switching element made of, for example, a thin-film transistor (TFT) is incorporated in each pixel of its liquid crystal display panel.
The active matrix type of liquid crystal display device has, as a chamber for a liquid crystal, a pair of substrates (at least one of which is a so-called transparent substrate having a sufficient optical transmissivity) which are arranged to oppose each other across the liquid crystal, and a pixel group is formed in a direction in which the liquid crystal is spread along the main surface of this substrate. This pixel group includes pixels each of which is provided in a portion surrounded by two adjacent ones of a plurality of scanning signal lines formed over the main surface of one of the pair of substrates which faces the liquid crystal (a liquid crystal layer) and by two adjacent ones of a plurality of video signal lines formed to cross the plurality of scanning signal lines. Each of the pixels is provided with a switching element to be driven by a scanning signal supplied from one of the two adjacent scanning signal lines and a pixel electrode to which a video signal supplied from one of the two adjacent video signal lines via this switching element is to be applied.
In this structure, a signal from a scanning driving circuit is inputted from one end of each of the scanning signal lines, while a signal from a video signal driving circuit is inputted from one end of each of the video signal lines. These driving circuits are mounted on the periphery of one of the substrates (the transparent substrate).
Each of the driving circuits is arranged to receive an input signal from a control circuit or the like which is mounted on, for example, a printed circuit board, but in this case, the transmission of signals to the driving circuits is effected by a flexible wiring board connected between the printed circuit board and one of the substrates of the liquid crystal display panel (for example, the transparent substrate on which the driving circuits are mounted).
The aforementioned flexible wiring board (also called “the flexible printed circuit board”, or “FPC” as its abbreviation) being utilized for the liquid crystal display device is disclosed in e.g. the Japanese Patent Laid-Open Nos. 270814/1995, 123489/1998, 38430/1999, and 52409/1999.